1. Field of the Invention
The present invention relates generally to rechargeable batteries and, more specifically, to a modular battery system providing different connector geometries for use with electronic devices such as camcorders, cellular phones, and portable computers.
2. Description of Related Art
The miniaturization of electronics has provided society with numerous portable electronic devices. The list is long, but such devices include portable computers, camcorders, and cellular phones. Portable electronic devices invariably require batteries.
Rechargeable batteries are often used because they are much cheaper than disposable batteries in the long run. The technology of battery recharging systems, however, has not kept pace with the needs of users.
For example, the typical owner of a camcorder is probably burdened by two or three rechargeable battery packs and a single "charging station" for recharging the battery packs when they are not in use. Charging stations supplied with camcorders or other portable devices are generally bulky and require a power cord for operation. In this case, if the camcorder is to be used for an extended period of time, it is necessary to carry extra batteries, the charging station, or both. Although miniaturization has made the battery-operated device easy to carry, the need for battery replacement or charging makes the portability of the end solution questionable.
Another problem with rechargeable systems is the variety of line voltages encountered around the world. A recharger designed for one country ordinarily requires an "adapter" for use in another country. This further impacts portability by requiring the user to carry another device when travelling.
Another problem faced by the user is the potential for some rechargeable batteries to exhibit a reduction in capacity due to the battery being subjected to repetitive shallow discharge and charge cycles. This can create a "memory" effect that makes the battery unable to deliver its rated charge. In order to eliminate this effect, it is recommended to discharge the battery to a low level before charging. Many users will purchase an additional unit called a "conditioner" to accomplish the discharge cycle before charging. This can result in yet another device being carried.
Another significant aspect of charging batteries is the effect of overcharging the batteries. A battery which is overcharged is unable to convert charge energy into stored energy. The charge energy is converted to heat which, over time, will reduce the capacity of the battery dramatically, and may even cause complete battery failure. Most users are not able to closely monitor the amount of time a battery spends under charge. Therefore, unless the charging station affords overcharge protection, the useful life of the battery may be shortened.
An additional burden on the user of rechargeable batteries is knowing the current capacity of the battery. If not known, the user must either guess and chance a failure at a critical time, or must preemptively charge the battery. Even when batteries have been fully charged, they lose capacity during storage due to an internal loss called "self-discharge."
A single unit that simply includes a charger and rechargeable batteries does not resolve the foregoing problems. The unit must be compact and lightweight since the charger is always present. Moreover, the combination may create other problems. For example, since the charger is likely to be usable even after the batteries require replacement, a combination charger/battery pack may be more costly than necessary since the system must be purchased and replaced as a unit.